une déformation non-élastique des accessoires

15:10 Oct 30, 2015 

There's nothing wrong with "plastic yield" (though slightly tautologous), and it means exactly the same as "inelastic deformation". Most solids show a linear stress-strain relationship for small loads, but at greater loads internal slippage at the microcrystalline level takes place, meaning that the material does not return to its original position. Emgineers refer to this point as the "yield point". "Strain" is a dimensionless quantity defined as the ratio of the displaced length to the original length, and is frequently (incorrectly) equated by the layman to stress.